With Rubin out at Android, Chrome integration may be about to begin.

Android head Andy Rubin is stepping aside, and that could mean big changes for Google's mobile platform and for its Chrome operating system.

Google CEO Larry Page announced the move in a blog post on Wednesday, saying Rubin will remain with the company but will take on a new role. Rubin, who is Google's senior vice president for mobile and digital content, joined Google in 2005, when the search giant acquired Android, then a startup company that Rubin had co-founded.

Sundar PichaiAndy Rubin

"The pace of innovation has never been greater, and Android is the most used mobile operating system in the world," Page wrote. "Having exceeded even the crazy ambitious goals we dreamed of for Android, and with a really strong leadership team in place, Andy's decided it's time to hand over the reins and start a new chapter at Google."

Page said Sundar Pichai, Google's senior vice president of Chrome and Apps, will take Rubin's place and will lead both the Chrome and Android divisions.

"Sundar has a talent for creating products that are technically excellent yet easy to use -- and he loves a big bet," wrote Page. "So while Andy's a really hard act to follow, I know Sundar will do a tremendous job doubling down on Android as we work to push the ecosystem forward."

Industry analysts said they were surprised by the news, and some wonder whether Rubin decided himself to move on or if he was asked to step aside. Regardless of why he's leaving, this is a big shift for Android.

Rubin brought Android to prominence on the global mobile stage, creating a two-horse race with Apple's iOS. With more than 60 partners, Android has become the most popular smartphone operating system in the U.S.

"[Rubin has been] working his tail off on Android, and he's made it extremely successful," said Jack Gold, an analyst at J.Gold Associates. "I don't think anyone can say he hasn't been pretty damn successful.... They have become a major mobile leader. Could he have done it faster, better, smoother? Sure... but I haven't seen any huge mistakes."

Gold said he doubted Rubin was pushed out. He speculated that Rubin probably wants to try his hand at something new.

"Every so often these guys have to take a breath and say, 'I've done a really good job, but where do I go from here?'" Gold said. "He's got a lot of creative juices. He may want to go do some new things and start something else. They said he'll stay at Google. I'd be surprised if he left. He's got a lot of freedom and opportunities there."

However, Patrick Moorhead, an analyst at Moor Insights & Strategy, said it's possible that Rubin was asked to make way for Pichai. He pointed out that Rubin is known as someone who's well suited to getting an idea off the ground, and it could be that Google now wants someone else to keep Android moving forward.

"Rubin is a classic entrepreneur, and Android, while far from mature, is in growth mode. Others are better suited to take Android to the next level," Moorhead said. "It's uncertain what happened exactly to Rubin, but given that his next role isn't defined, this probably means he was pushed aside."

Another interesting part of the announcement, according to both analysts, is that Google chose to replace Rubin with someone who has been leading, and will continue to lead, Chrome.

"We will see more of a maturing of Android, which is exactly what it needs right now," said Moorhead. "Chrome and Android will be coming together, something the industry knew had to happen ultimately. Giving the top job to the Chrome leader nearly ensures this is the case."

Gold said he doesn't think Android and Chrome should have been developed separately and noted that it's a natural move to bring them together.

"As Chrome becomes a richer OS, I think you'll see some of the underpinnings of Android move in there," said Gold, who added that the integration may not happen immediately. "I think you'll see some of the kernel of Android, not all of it, move over. The Java machine, some of the driver capabilities and some components, will move over, and maybe some of the Android apps, like Google Play, could make it into Chrome and the Chromebook as native apps."

Users, though, shouldn't notice much of a change under Pichai's leadership -- at least not in the short term.

"I don't think anyone will even notice, to be honest with you, three months from now, six months from now," said Gold. "I think for the market, this will just be a minor glitch. But a year or two out with a new head, you don't really know what is going to happen."